Technical Field
The inventions relate to microwave and millimeter waveguide devices and methods and devices that use such waveguide devices.
Related Art
This section introduces aspects that may be help to facilitate a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is prior art or what is not prior art.
In electronic systems, a variety of multi-port waveguide devices are known. One such multi-port waveguide device is the Wilkinson power divider.
FIG. 1 schematically illustrates a symmetric type of Wilkinson power splitter 10_w. The Wilkinson power splitter 10_w includes a 1×2 waveguide coupler 12_w and first and second internal waveguides 14_w, 16_w. The 1×2 waveguide coupler 12_w divides the power of the signal received via input waveguide 2_w equally between two output ports. The first end of each internal waveguide 14_w, 16_w end-connects to a corresponding one of the output ports of the 1×2 waveguide coupler 12_w. The second end of each internal waveguide 14_w, 16_w forms an output of the Wilkinson power divider, e.g., which may end-connect to an output waveguide 4_w, 6_w. Each internal waveguide 14_w, 16_w has a length configured to accommodate half of the wavelength of electromagnetic signals at the frequency that the Wilkinson power splitter 10_w is desired to provide power splitting. In configurations where the Wilkinson power divider 10_w is a planar device, the labeled elements 2_w, 4_w, 6_w, 12_w, 14_w, 16_w of FIG. 1 may be, e.g., the metal traces of microwave stripline or microstrip waveguides.
The Wilkinson power divider 10_w also includes a lumped ohmic shunt 28_w that connects the second or output ends of the internal waveguides 14_w, 16_w. For example, the lumped ohmic shunt 28_w electrically and physically connects the ends of the metal traces of the striplines or microstrips in microwave stripline or microstrip forms of the internal waveguides 14_w, 16_w. The lumped ohmic shunt 28 is small compared to the wavelength of the electromagnetic signals that the Wilkinson power divider 10_w is configured to power divide.
Over a narrow frequency range, a Wilkinson power divider can efficiently power split a received electromagnetic signal. For example, the Wilkinson power divider 10_w of FIG. 1 may split an electromagnetic signal such that each output waveguide 4_w, 6_w receives about half of the power of a microwave electromagnetic signal received from the input waveguide 2_w. A Wilkinson power divider also has the advantage of isolating waveguides or devices connected to the output ports thereof. For example, the Wilkinson power divider 10_w of FIG. 1 may be configured to strongly isolate the two output waveguides 4_w, 6_w from each other. For appropriate matching, a Wilkinson power divider is a low loss 3-port waveguide device for power splitting a received electromagnetic signal in a narrow frequency range.